Background and objective: Ultrasound-guided blocks of the cervical plexus are established anesthetic procedures for carotid endarterectomy. This randomized, double-blind, placebo-controlled study tested the hypothesis that an additional ultrasound-guided periarterial injection of local anesthetic leads to a lower frequency of periarterial supplementation by the surgeon.
Methods: A total of 40 patients were randomly assigned to 1 of 2 groups. In both groups an ultrasound-guided intermediate cervical plexus block (20 ml of 0.75 % ropivacaine) at the level of the fourth cervical vertebra was performed. In a second step, the needle was inserted from posterolateral to anteromedial (in-plane technique) relative to the internal carotid artery and then, depending on the randomized group assignment, 5 ml of 0.75 % ropivacaine (group 2) or 5 ml of 0.9 % saline (group 1) was injected. The parameters investigated included the need for supplementation, patient comfort, the incidence of side effects and circulatory changes.
Results: The two groups did not significantly differ (p = 0.459) in terms of the need for intraoperative supplementation with 1 % prilocaine with a mean (range) in group 2 of 4.9 ml (0-20 ml), in group 1 of 3.7 ml (0-16 ml) and patient comfort (p = 0.144). In addition, a trend towards a higher complication rate was observed in group 2.
Conclusion: For ultrasound-guided intermediate blocks of the cervical plexus, an additional periarterial infiltration showed no advantage. Abandoning this technique leads to a relevant simplification of the blocking technique and tends to reduce block-related side effects.
Keywords: Anesthesia, regional; Cervical plexus; Internal carotid artery stenosis; Randomized controlled trial; Ultrasonography.